Effect of pre-annealing on thermal stability of amorphous Zr-Cu-Ni alloy

The influence of pre-annealing on thermal stability of the amorphous Zr70Cu20Ni10 alloy was reported by em-ploying the differential scanning calorimetry (DSC) and high-resolution transmission electron microscopy (HRTEM) tech-niques. It has been observed that the supercooled liquid region decreases with increasing the annealing time under isothe-mal conditions, indicating that the thermal stability of the amorphous Zr70Cu20Ni10 alloy decreases gradually. HRTEM ob-servations reveal that there exist some ordered atomic clusters in the amorphous matrix at the relaxation stage. These or-dered atomic clusters can be regarded as precursors for the precipitation of the crystalline phases in the subsequent crystal-lization process. The reasons resulting in the decrease in thermal stability of the amorphous Zr70Cu20Ni10 alloy with anneal-ing time are discussed through the Gaussian decomposition for the radial distribution function of the amorphous Zr70Cu20Ni10 alloy.     

电脉冲孕育处理对Zr基块体非晶热稳定性及退火晶化的影响

通过先对Zr55Ni5Al10Cu30合金熔体施加脉冲电流处理,再利用非真空吸铸法制备出Zr55Ni5Al10Cu30块体非晶合金的方式,研究了电脉冲孕育处理对非晶热稳定性及退火晶化的影响。差分扫描量热(DSC)及X射线衍射(XRD)分析结果表明:经电脉冲孕育处理后Zr55Ni5Al10Cu30块体非晶合金的玻璃转变温度上升,晶化温度降低,过冷液相区变窄,同时玻璃转变激活能和晶化激活能有所减少。电脉冲孕育处理没有改变Zr55Ni5Al10Cu30块体非晶合金退火晶化相演变过程,但提高了非晶退火晶化率。电脉冲孕育处理对Zr55Ni5Al10Cu30块体非晶合金的晶化起到了促进作用。     

Microstructure and mechanical properties of Zr-Cu-Al bulk metallic glasses

Zr49Cu46Al5 and Zr48.5Cu46.5Al5 bulk metallic glasses（BMGs） with diameter of 5 mm were prepared through water-cooled copper mold casting. The phase structures of the two alloys were identified by X-ray diffractometry（XRD）. The thermal stability was examined by differential scanning calorimetry（DSC）. Zr49Cu46Al5 alloy shows a glass transition temperature, Tg, of about 689 K, an crystallization temperature, Tx, of about 736 K. The Zr48.5Cu46.5Al5 alloy shows no obvious exothermic peak. The microstructure of the as-cast alloys was analyzed by transmission electron microscopy（TEM）. The aggregations of CuZr and CuZr2 nanocrystals with grain size of about 20 nm are observed in Zr49Cu46Al5 nanocrystalline composite, while the Zr48.5Cu46,5Al5 alloy containing many CuZr martensite plates is crystallized seriously. Mechanical properties of bulk Zr49Cu46Al5 nanocrystalline composite and Zr48.5Cu46.5Al5 alloy measured by compression tests at room temperature show that the work hardening ability of Zr48.5Cu46.5A15 alloy is larger than that of Zr49Cu46Al5 alloy.     

Crystallization kinetics of amorphous Zr65Cu25Al10 alloy

1　ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｄｅｖｅｌｏｐｍｅｎｔｏｆｇｌａｓｓｆｏｒｍｉｎｇ ｍｕｌｔｉｃｏｍｐｏ ｎｅｎｔａｌｌｏｙｓｙｓｔｅｍｓｗｉｔｈｖｅｒｙｌｏｗｃｒｉｔｉｃａｌｃｏｏｌｉｎｇｒａｔｅｓｗｉｔｈｉｎ 1～ 10 0Ｋ/ｓｈａｓｏｆｆｅｒｅｄｆｉｒｓｔ     

Zr55Al10Ni5Cu30块状非晶合金靠近玻璃转变点的等温纳米晶化

研究了Zr55Al10Ni5Cu30块状非晶合金靠近玻璃转变点等温晶化过程。结果表明：420℃退火5h,出现了尺寸为20nm左右的晶相,同时,非晶基体也出现了尺寸为1－2nm分布均匀的团簇状结构;退火10h,析出的晶相尺寸为20－50nm,所占的体积分数为40％;退火20h之后,非晶相完全转变为亚稳相,析出的晶相尺寸为50nm左右,并没有出现明显的长大现象。退火得到的晶相为Cu10Zr7,Zr2Ni及一些未能标定的相,这些相在420℃具有相对的稳定性,没有问题稳定相转变。退火后,残余非晶相的热稳定性降低。等温退火过程经历了从非晶相→团簇状结构→亚稳相的转变过程。     

Cu64Zr36非晶合金的晶化动力学

利用单辊急冷法制备了CH64Zr36非晶合金，使用盐浴等温退火并用DSC和XRD研究了其晶化过程、玻璃转变和晶化动力学。结果表明：CH64Zr36非晶合金的晶化过程为：非晶一非晶＋Cu10Zr7→Cu10Zr7＋CuZr2。该合金的玻璃转变和晶化激活能分别为433．7kJ／mol和603kJ／mol。     

Zr60Al15Ni25大块非晶合金晶化行为的原位XRD分析

利用差示扫描量热法(DSC)和原位X射线衍射法(In Situ XRD)研究了Zr<,60>Al<,15>Ni<,25>大块非晶合金的晶化行为.DSC研究结果表明,合金的玻璃转变温度Tg、品化开始温度Tx、晶化峰温度T<,p>分别为407.0℃、482.4℃和496.9℃,过冷液相区△Tx为75.4℃,合金具有良好的热...     

Zr-Ti-Cu-Ni-Be大块非晶合金等温晶化过程相分离研究

利用差示扫描量热法(DSC)和透射电镜(TEM)对Zr41.2Ti13.8Cu12.5Ni10Be22.5(at％)大块非晶合金的等温晶化过程和析出相进行了研究。结果表明，大块非晶合金在等温晶化过程中表现出多阶段相析出行为，并且在不同的晶化阶段，析出相也有所不同。在第1个晶化阶段，析出相主要是体心四方(b.c．t)结构的Zr2Cu相；而在晶化的第2个阶段，晶化相主要为简单六方结构的ZrBe2相。从一定程度上证实了Zr41.2Ti13.8Cu12.5Ni10Be22.5大块非晶合金在发生晶化时会形成富Zr区和富Be区，即有相分离的趋势。XRD测试的结果也证实了非晶合金在发生完全晶化时，主要的晶化产物为Zr2Cu和ZrBe2相。     

Structures of bulk amorphous Zr_(41) Ti_(14) Ni_(10) Cu_(12.5) Be_(22.5)alloy in amorphous, crystalline, supercooled liquid and liquid states

1　ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｂｕｌｋａｍｏｒｐｈｏｕｓａｌｌｏｙｓｏｆＭｇ ＴＭ Ｌｎ ,Ｌｎ Ａｌ ＴＭ ,Ｚｒ Ａｌ ＴＭ ,Ｈｆ Ａｌ ＴＭａｎｄＴｉ Ｚｒ ＴＭｗｅｒｅｐｒｅｐａｒｅｄｂｙＩｎｏｕｅａｎｄｈｉｓｃｏ ｗｏｒｋｅｒｓｓｉｎｃｅ 1990 [1] .Ｔｈｅｃ     

Cu坯料纯度对Cu46Zr42Al7Gd5合金非晶形成能力与显微硬度的影响

采用铜模吸铸法制备直径为3 mm的Cu46Zr42Al7Gd5块体非晶合金;研究Cu坯料纯度对该合金非晶形成能力、热稳定性和显微硬度的影响.结果表明:采用纯度较低的Cu坯料,分别以25%和50%的比例替代纯度较高的Cu坯料后,仍可制备直径为3 mm的非晶态合金;当替代比例提高到75%或更高时,合金呈现完全晶态相;当替代比例为25%时,合金的玻璃化转变温度为669 K,晶化温度为749 K,过冷液相区为80 K;当替代比例为50%时,合金的玻璃转化温度为684 K,晶化温度为751 K,过冷液相区为67 K;两种替代比例(25%和50%)的合金经573 K保温1 h热处理后,仍然保持非晶态结构;当替代比例为25%时,合金经673和773 K热处理后,合金由基体及弥散分布于其上的第二相组成,显微硬度明显提高;当替代比例为50%时,经673 K处理后,合金由基体及不均匀弥散分布于其上的第二相组成,显微硬度有所提高,而经773 K处理后,由第二相弥散分布于白色基体的白色区域和由细小白、灰两相混合组成的灰色区域组成,显微硬度大幅度提高.     

Nanostructured bulk glassy Cu_(60)Zr_(30)Ti_(10) alloy with high strength and good ductility in cast state

1　INTRODUCTIONSinceaseriesofmetallicbulkglassyalloyswithexpectedmechanicalpropertiesandhighglassformingabilityhavebeenfound[13] ,particularattemptshavebeendonetoimprovethemechanicalpropertiesoftheglassyalloystomeetengineeringapplications .Bycrystallizingthemetallicglasses ,nanostructuredal loyscontainingnanocrystallinephasesandglassyma trixwereobtainedandthemechanicalpropertiesofthealloyswereenhancedbyhomogeneousdispersionofnanoscalemetallic particlesintheAl [4 ,5] ,Fe Ni [6 ] andMg [7]…     

(Zr0.55Cu0.3Al0.1Ni0.05)98Er2非晶合金制备及其晶化动力学行为

为了研究SAF2507双相不锈钢（SAF2507 DSS）螺旋桨叶片在含硫酸盐还原菌( SRB)和铁氧化菌(IOB)海水中的耐腐蚀性能,提出一种二次急冷淬火成形技术来成形SAF2507 DSS螺旋桨叶片。同时根据螺旋桨叶片在不同二次急冷淬火成形温度下析出相的类型和析出规律,研究螺旋桨叶片在含SRB和IOB海水中的腐蚀性能。结果表明,当二次急冷淬火成形温度在700℃时,螺旋桨叶片表面析出少量的χ相;达到850℃时,χ相停止析出并完全转化成σ相,析出的σ相达到最大值;超过850℃时,析出的σ相开始急剧减少,到950℃时仅有少量的σ相析出。螺旋桨叶片在不同二次急冷淬火成形温度下,腐蚀电流密度、交流阻抗等电化学性能变化规律与螺旋桨叶片表层χ相和σ相的析出规律、以及χ相和σ相自身的耐腐蚀特征相吻合。二次急冷淬火成形温度在750℃-1050℃之间,螺旋桨叶片的耐腐蚀性能随热成形温度的升高呈增强—降低—增强规律变化,850℃时螺旋桨叶片的耐腐蚀性能最差。螺旋桨叶片二次急冷淬火成形后富Fe的表面特征,在SRB+IOB的作用下,螺旋桨叶片表面钝化膜被破坏,导致耐腐蚀性能降低。     

二次急冷淬火成形SAF2507双相不锈钢螺旋桨在SRB+IOB海水中的腐蚀行为

为了研究SAF2507双相不锈钢（SAF2507 DSS）螺旋桨叶片在含硫酸盐还原菌( SRB)和铁氧化菌(IOB)海水中的耐腐蚀性能,提出一种二次急冷淬火成形技术来成形SAF2507 DSS螺旋桨叶片。同时根据螺旋桨叶片在不同二次急冷淬火成形温度下析出相的类型和析出规律,研究螺旋桨叶片在含SRB和IOB海水中的腐蚀性能。结果表明,当二次急冷淬火成形温度在700℃时,螺旋桨叶片表面析出少量的χ相;达到850℃时,χ相停止析出并完全转化成σ相,析出的σ相达到最大值;超过850℃时,析出的σ相开始急剧减少,到950℃时仅有少量的σ相析出。螺旋桨叶片在不同二次急冷淬火成形温度下,腐蚀电流密度、交流阻抗等电化学性能变化规律与螺旋桨叶片表层χ相和σ相的析出规律、以及χ相和σ相自身的耐腐蚀特征相吻合。二次急冷淬火成形温度在750℃-1050℃之间,螺旋桨叶片的耐腐蚀性能随热成形温度的升高呈增强—降低—增强规律变化,850℃时螺旋桨叶片的耐腐蚀性能最差。螺旋桨叶片二次急冷淬火成形后富Fe的表面特征,在SRB+IOB的作用下,螺旋桨叶片表面钝化膜被破坏,导致耐腐蚀性能降低。     

Zr57Nb5Cul5．4Nil2．6Al10大块非晶合金的晶化动力学及显微硬度

采用铜模铸造法制备直径10mm的圆柱状Zr57Nb5Cu15.4Ni12.6Al10大块非晶合金，并用X射线衍射(XRD)证明其为完全非晶态。应用示差扫描量热(DSC)分析方法测定该合金的玻璃转变的热学参量并分析其晶化过程。利用Kissinger法和Ozawa法计算了大块非晶合金表观晶化激活能。同时研究了退火温度对非晶合金显微硬度的影响。     

Zr-Al-Ni-Cu-Nb块体非晶复合材料的制备及热稳定性

采用结构分析和热分析手段研究了Nb对Zr65(Cu0.4Al0.3Ni0.3)35-xNbx(x=0, 3, 5, 6 7) (at%)合金玻璃形成能力和热稳定性的影响,采用铜模吸注法成功制备了非晶基体上均匀分布枝晶相的Zr65(Cu0.4Al0.3Ni0.3)28Nb7块体非晶复合材料.Nb的添加导致合金的过冷液相区间的宽度显著减小,同时,Nb的加入使得合金的原子结构更加无序化,因而合金具有更好的热稳定性.     

Zr55Al10Cu30Ni5-xPdx块状非晶合金的玻璃形成能力和热稳定性

用铜模铸造方法制备了不同尺寸的Zr55Al10Cu30Ni5-xPdx(x=0,1,3,5)块状非晶合金，采用X射线衍射（XRD）、扫描差热分析（DSC）和透射电镜（TEM）分别为Zr55Al10Cu30Ni5-xPdx块状非晶样品的结构、热稳定性和微观组织进行了研究。结果表明：x=1时，合金具有最高的过冷液相区（高达100K）及最大的热稳定性，而对合金的玻璃形成能力影响不大，这说明用适量的Pd代表Zr55Al10Cu30Ni5合金中的Ni会提高合金的热稳定性；x=3时，合金的热稳定性有所提高，但降低了合金的玻璃形成能力；x=5时，非晶合金的热稳定性和玻璃形成能力同时降低。     

Effect of heat treatment on structure and magnetic properties of Fe65.5Cr4Mo4Ga4P12C5B5.5 bulk amorphous alloy

This study deals with the Fe65.5Cr4Mo4Ga4P12C5B5.5 ferromagnetic bulk amorphous alloy. XRD analysis showed an amorphous structure of the as-cast sample. The same method revealed that, after annealing at 973 K for τ=10 min, the sample displayed a crystalline structure with crystalline phases formed. The crystallization process of the alloy was examined by DTA analysis. It was shown that crystallization took place in the temperature range between 810 K and 860 K with the exo-maximum peak temperature at 846 K with a heating rate of 20 K·min-1. The method also showed that, at temperatures ranging from 753 K to 810 K, the alloy exhibited the properties of supercooled liquids. A correlation between heat-induced structural changes and magnetic properties of the alloy was determined by thermomagnetic measurements. Maximum magnetization M=3.7 Am2·kg-1 of the alloy was reached after its annealing at 733 K for τ=10 min. Upon annealing, the alloy exhibited a relaxed amorphous structure. Annealing the alloy above the crystallization temperature led to a decrease in bulk magnetization. After annealing at 973 K for τ=10 min, the bulk magnetization of the alloy was M'=0.45 Am2·kg-1. Accordingly, after crystallization and formation of new compounds, the magnetization of the alloy was decreased by a factor of about 7.7. The strength of the magnetic field applied during the measurements was H=10 k A·m-1. The samples were tested for changes in the microstructure and hardness of both the amorphous phase and the resulting crystalline phase.     

喷射成形La62Al15.7(Cu,Ni)22.3块体非晶合金的晶化行为

研究了喷射成形和铜模吸铸法制备的La62Al15.7(Cu,Ni)22.3块体非晶合金的晶化行为。结果表明,两种工艺制备的非晶合金晶化过程都为三级晶化,晶化的顺序为:非晶→非晶+La→非晶+La+Al3La→非晶+La+Al3La+富Cu和Ni的未知相。结合晶化动力学计算和退火晶化实验结果表明,低温(<503K)时,喷射成形La62Al15.7(Cu,Ni)22.3非晶合金的热稳定性优于铜模吸铸La62Al15.7(Cu,Ni)22.3非晶合金,高温(>553K)时结果相反。     

Thermal stability of B2 CuZr phase,microstructural evolution and martensitic transformation in Cu–Zr–Ti alloys

The effects of minor Ti addition on the thermal stability of B2 CuZr phase, the microstructure and the martensitic transformation (MT) in Cu₅₀Zr_50−xTi_x (x = 0, 2.5, 7.5 and 10 at%) alloys were investigated. It was found that the crystallization products, i.e. Cu₁₀Zr₇ and Cu(Ti, Zr)₂, of Cu–Zr–Ti amorphous alloys transform to B2 CuZr phase at high temperatures. The corresponding eutectoid transformation temperature gradually increases with increasing Ti content, implying the decrease of the thermodynamic stability of the B2 CuZr phase. The microstructures of Cu–Zr–Ti martensitic alloys were proven to contain B2 CuZr, CuZr martensite, Cu₁₀Zr₇, Cu(Ti, Zr)₂, and ZrTiCu₂ crystals. Dilatometric measurements reveal that the MT temperature reduces with increasing Ti content, which would be of electronic nature. With increasing thermal cycles, the MT temperature gradually decreases while the reverse MT temperature increases, which results from the enhancement of the dislocation density, the partial decomposition of the equiatomic CuZr crystals and the partially reversible MT.     

Zr65Al10Ni10Cu15非晶合金电阻率的研究

在不同加热速率下利用恒流四电极法研究了非晶合金Zr65Al10Ni10Cu15的电阻率随温度的变化情况,根据电阻率随温度的变化情况可以把晶化前的温度区间分为3个阶段,第一和第二阶段分别对应于低温结构弛豫和高温度结构弛豫发生的温度区间,而第三阶段的变化情况与前二个阶段明显不同,并在晶化前出现电阻率极大值峰。研究表明,利用电阻率随温度的变化情况,可以反映出非晶更多的结构转变的信息。